Heretofore sundials made of clear cylinders have been known, as for example, in the U.S. patent to Putnam, U.S. Pat. No. 2,846,768, and somewhat similar sundials have been shown in U.S. patent to Carlson, U.S. Pat. No. 3,786,570, and traditional sundials with flat plates and angularly disposed gnomons have been known for centuries. Hemispherical sundials were made by Berosus before the Christian era, and continued in use as late as 900 A.D. See Vol. 7, Encyclopedia Britannica, 14th Ed. pp. 310-314.
The present invention comprises a single block of translucent, preferably transparent material graduated to indicate time from before 7:00 a.m. to after 5:00 p.m. It does this without any moving parts. It can be small enough to be used on a window sill, or any other place where it can be exposed to the sun. It can be made of clear plastic or glass so that it is not seriously injured by weathering. It also forms a convenient device for use in instructing students in the relationship of the sun and the earth.